JP6848690B2 - Fuel system controller - Google Patents

Description

The present invention relates to a fuel system control device.

Conventionally, a fuel system control device that can continuously secure high filtration efficiency by controlling heating by a heater of a fuel filter that filters fuel into a combustion chamber in the fuel system of an internal combustion engine is widely known. ..

In the device disclosed in Patent Document 1 as a kind of such fuel system control device, heating of the fuel filter by heater control is executed based on the kinematic viscosity and temperature of the fuel according to the correlation data of the cloud point with respect to the kinematic viscosity of the fuel. There is.

Japanese Unexamined Patent Publication No. 2014-51920

However, as a result of diligent research by the present inventors, even if the fuel has the same kinematic viscosity at a certain single temperature, the degree of growth of precipitated crystals due to waxing differs depending on the difference in the constituent components, and the cloud point becomes cloud point. It turns out to be different. Therefore, in the disclosure device of Patent Document 1, even if the correlation data of the cloud point with respect to the kinematic viscosity is used, heating is not executed even though the current temperature is below the cloud point depending on the components of the fuel, and the fuel is not executed. There was a concern that the fuel in the filter would wax and in the worst case cause clogging. Here, once the fuel is waxed, the precipitated crystals adhering to the fuel filter are difficult to melt even when heated, so it is necessary to take measures to continuously secure high filtration efficiency.

The present invention has been made in view of the problems described above, and an object of the present invention is to provide a fuel system control device for continuously ensuring high filtration efficiency of a fuel filter.

Hereinafter, the technical means of the invention for achieving the subject will be described. The scope of claims for disclosing the technical means of the invention and the reference numerals in parentheses described in this column indicate the correspondence with the specific means described in the embodiment described in detail later. It does not limit the technical scope of the invention.

The invention disclosed to solve the above-mentioned problems is
A fuel system control device (50) that controls heating by a heater (110) of a fuel filter (11) that filters fuel supplied to a combustion chamber (1a) in the fuel system (10) of an internal combustion engine (1). ,
Parameter acquisition blocks (S102, S103, S3101, S4101, S4103, S5101, S5103) for acquiring property parameters (KVp, DDp, KVp1, KVp2, DDp1, DDp2) representing the properties of the fuel, and
Based on the property parameters acquired by the parameter acquisition block, the average calculation block (S104, S2104, S3104, S4104, S5104) for calculating the average number of elements (NC, NH) of the components constituting the fuel, and
A cloud point estimation block (S105) that estimates the cloud point (TMc) of the fuel corresponding to the average number of elements calculated by the average calculation block, and
A heater control block (S107, S108) for heating the fuel filter by controlling the heater at the fuel temperature (TMj) estimated by the cloud point estimation block to be equal to or lower than the cloud point is provided.

In such a disclosed invention, the cloud point of the fuel is estimated in correspondence with the average number of elements of the fuel constituents calculated based on the property parameters of the fuel. According to this, since the cloud point can be estimated even if the fuel components are different, the fuel filter can be heated under the control of the heater at the fuel temperature below the cloud point to prevent waxing prior to clogging. Therefore, it is possible to continuously secure the filtration efficiency of the fuel filter.

It is a block diagram which shows the fuel system of the internal combustion engine to which 1st Embodiment is applied. It is a flowchart which shows the heating control flow of 1st Embodiment. It is a graph for demonstrating the calculation of the average carbon number of 1st Embodiment. It is a graph for demonstrating the estimation of the cloud point of 1st Embodiment. It is a flowchart which shows the heating control flow of 2nd Embodiment. It is a graph which shows the model data example of the 2nd Embodiment. It is a graph which shows the model data example of the 2nd Embodiment. It is a flowchart which shows the heating control flow of 3rd Embodiment. It is a flowchart which shows the heating control flow of 4th Embodiment. It is a flowchart which shows the heating control flow of 5th Embodiment.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. By assigning the same reference numerals to the corresponding components in each embodiment, duplicate description may be omitted. When only a part of the configuration is described in each embodiment, the configuration of the other embodiment described above can be applied to the other parts of the configuration. Further, not only the combination of the configurations specified in the description of each embodiment but also the configurations of a plurality of embodiments can be partially combined even if the combination is not specified.

(First Embodiment)
As shown in FIG. 1, the ECU (Electronic Control Unit) 50 as the "fuel system control device" according to the first embodiment of the present invention is applied to the fuel system 10 of the internal combustion engine 1 mounted on the vehicle. The ECU 50 controls heating by the heater 110 of the fuel filter 11 that filters the fuel supplied to the combustion chamber 1a of the internal combustion engine 1.

Specifically, the fuel system 10 includes a fuel tank 12, a fuel filter 11, a high-pressure fuel pump 13, a common rail 14, a temperature sensor 15, a kinematic viscosity sensor 16, a density sensor 17, and the like. The fuel tank 12 stores the supply fuel in the combustion chamber 1a.

The fuel filter 11 is configured by accommodating a filter element 111 such as a filter paper in a container 112. The filter element 111 passes the fuel supplied from the fuel tank 12 to the combustion chamber 1a in the middle of the supply path. At this time, the filter element 111 filters the passing fuel by collecting foreign substances in the passing fuel.

A heater 110 is installed in the container 112 of the fuel filter 11. The heater 110 is mainly composed of a heat generating element such as a PTC (Positive Temperature Coefficient) element. The heater 110 receives heating control of the filter element 111 by adjusting the energization from the ECU 50. As a result, the filter element 111 can exert a deterrent effect against waxing that begins to occur prior to clogging at cloud points corresponding to the fuel components constituting the fuel.

The high-pressure fuel pump 13 pumps the fuel sucked from the fuel tank 12 through the fuel filter 11 to the common rail 14 as the fuel to be supplied to the combustion chamber 1a. Therefore, the high-pressure fuel pump 13 receives pressure control of the pumped fuel to the common rail 14 by adjusting the energization from the ECU 50. At this time, the pressure of the pumped fuel to the common rail 14 is controlled by the ECU 50 based on the operating state of the internal combustion engine 1 such as the accelerator opening degree and the engine speed.

The common rail 14 temporarily stores the supply fuel injected from the fuel injection valve 1b for each of the plurality of combustion chambers 1a in the internal combustion engine 1. Here, the on-off valve timing of each fuel injection valve 1b for each combustion chamber 1a is controlled by the ECU 50. As a result, when each fuel injection valve 1b is opened, the fuel supplied from the common rail 14 is injected into the corresponding combustion chamber 1a, and the fuel is mixed with the air sucked into the corresponding combustion chamber 1a. As a result, the air-fuel mixture is compressed by the piston of the internal combustion engine 1, and the fuel self-ignites and burns. That is, the internal combustion engine 1 of the present embodiment is a compression self-ignition type diesel engine, and diesel fuel (light oil) is used as the fuel to be supplied to the internal combustion engine 1. Here, the constituents of such fuels differ from region to region (country to country) in the world.

A pressure reducing valve 140 is installed on the common rail 14 in order to regulate the pressure of the internal fuel from exceeding the pressure resistance value. As shown in FIG. 1, one of the fuel tank 12 and the fuel filter 11 may be selected by the recirculation valve 141 as the recirculation destination of the fuel released from the common rail 14 when the pressure reducing valve 140 is opened. Although not shown, the reflux destination may be limited to the fuel tank 12. The selection of the reflux destination by the reflux valve 141 is controlled by the action of the temperature sensitive element according to the fuel temperature. Also. The fuel whose recirculation destination is selected by the recirculation valve 141 may be not only the fuel released from the common rail 14, but also the fuel released from the high-pressure fuel pump 13 and each fuel injection valve 1b, as shown in FIG. ..

Each of the sensors 15, 16 and 17 is a predetermined location (not explicitly shown in FIG. 1) in the fuel path from the fuel tank 12 to each fuel injection valve 1b for each combustion chamber 1a in the fuel system 10. It is installed in. The temperature sensor 15 is mainly composed of a sensor element such as a thermistor. The temperature sensor 15 detects the temperature of the fuel supplied from the fuel tank 12 to the combustion chamber 1a at the installation location. The kinematic viscosity sensor 16 is mainly composed of a tuning fork type, an ultrasonic type, a thin tube type or the like direct measurement type, or an indirect estimation type sensor element from a density or the like. The kinematic viscosity sensor 16 detects the kinematic viscosity as a property parameter representing the properties of the fuel supplied from the fuel tank 12 to the combustion chamber 1a at the installation location. The density sensor 17 is mainly composed of a sensor element such as a natural vibration cycle measurement type. The density sensor 17 detects the density as a property parameter of the fuel supplied from the fuel tank 12 to the combustion chamber 1a at the installation location. Here, in particular, the detection of the density by the density sensor 17 and the detection of the kinematic viscosity by the kinematic viscosity sensor 16 are executed in the present embodiment at an installation location where the fuel temperature can be simulated as substantially the same.

The ECU 50 is mainly composed of a microcomputer having a processor 50a and a memory 50b. The ECU 50 is directly or indirectly connected to the heater 110, the high-pressure fuel pump 13, the sensors 15, 16, 17 and the valves 1b, 140, as well as various sensors of the vehicle, either directly or via an in-vehicle network. The ECU 50 controls the operation of the heater 110, the high-pressure fuel pump 13, and the valves 1b and 140 based on the vehicle information including the detection information of the sensors 15, 16 and 17 and the operating state of the internal combustion engine 1.

Here, in detail, the ECU 50 functionally realizes each step of the heating control flow shown in FIG. 2 by executing the heating control program stored in the memory 50b by the processor 50a. The heating control flow is started in response to an on operation of the power switch that gives a start command of the internal combustion engine 1 from the occupant in the vehicle, while an off operation of the switch that gives a stop command of the internal combustion engine 1 from the occupant. It ends accordingly. Further, "S" in the heating control flow means each step. Furthermore, the memory 50b of the ECU 50 that stores the heating control program is configured by using one or more storage media such as a semiconductor memory, a magnetic medium, or an optical medium.

First, in S101, the current temperature TMp of the fuel at the detection location of the kinematic viscosity and the density as the property parameters, that is, the installation location of the kinematic viscosity sensor 16 and the density sensor 17, is acquired based on the detection information by the temperature sensor 15. At this time, if the temperature sensor 15 detects the fuel temperature at the installation location or the vicinity location of the kinematic viscosity sensor 16 and the density sensor 17, the temperature detected by the temperature sensor 15 is directly acquired as the current temperature TMp. On the other hand, if the temperature sensor 15 detects the fuel temperature at a location separated from the installation location of the kinematic viscosity sensor 16 and the density sensor 17, the current temperature TMp is indirectly and estimatedly acquired from the temperature detected by the temperature sensor 15. To.

In the next S102, the current kinematic viscosity KVp of the fuel at the installation location of the kinematic viscosity sensor 16 is acquired based on the detection information of the kinematic viscosity sensor 16 under substantially the same temperature as the current temperature TMp acquired by S101. In the following S103, the current density DDp of the fuel at the installation location of the density sensor 17 is acquired based on the detection information of the density sensor 17 under substantially the same temperature as the current temperature TMp acquired by S101. That is, the current density DDp and the current kinematic viscosity KVp are acquired at the same temperature TMp.

Further in S104, the average number of carbon atoms NC and the average number of hydrogens NH are calculated as the average number of elements of the fuel component mainly containing carbon and hydrogen. According to the results of diligent research by the present inventor, it has been found that the current kinematic viscosity KVp and the current density DDp have the correlations of the following formulas 1 and 2 with respect to the average carbon number NC and the average hydrogen number NH.
NC = αt1, KVp + βt1, NH + γt1 ... (Equation 1)
NC = αt2, DDp + βt2, NH + γt2 ... (Equation 2)

Here, the coefficients αt1, βt1, γt1 of the equation 1 and the coefficients αt2, βt2, γt2 of the equation 2 are set in advance according to an arbitrary fuel temperature by, for example, based on an experimental result or a simulation result at the time of design. Will be done. Therefore, in the first embodiment, the coefficients αt1, βt1, γt1 and the coefficients αt2 set in advance for each fuel temperature are used as model data showing the correlation between the current kinematic viscosity KVp and the current density DDp with respect to the average carbon number NC and the average hydrogen number NH. , Βt2, γt2 are introduced, and equations 1 and 2 are followed by the calculation of S104. Specifically, in S104, among the sets of equations 1 and 2 in which the coefficients αt1, βt1, γt1 and the coefficients αt2, βt2, γt2 are substituted for each fuel temperature, the equations 1 and 2 corresponding to the current temperature TMp acquired by S101 Select the set of two. Subsequently, in S104, the current kinematic viscosity KVp and the current density DDp acquired by S102 and S103, respectively, are introduced into the selected set of equations 1 and 2. Further, in S104, the average carbon number NC and the average hydrogen number NH are calculated by solving the simultaneous equations of the set of equations 1 and 2 in which the current kinematic viscosity KVp and the current density DDp are introduced.

From the above description, in S104, the average carbon number NC and the average hydrogen number NH based on the current kinematic viscosity KVp, the current density DDp and the current temperature TMp are calculated according to equations 1 and 2 which are model data according to the fuel temperature. is there. FIG. 3 proves that the average carbon number NC thus calculated is substantially the same as the actual average carbon number NC according to the fuel constituents. When discrete values are adopted as the fuel temperature associated with Equations 1 and 2 in advance from the viewpoint of the storage capacity of the memory 50b, the coefficient αt1 calculated by interpolation is the current temperature TMp between the discrete values. βt1, γt1 and coefficients αt2, βt2, γt2 are introduced into equations 1 and 2.

In the following S105 as shown in FIG. 2, the cloud point TMc corresponding to the fuel component is estimated. According to the results of diligent research by the present inventor, it has been found that the cloud point TMc can be estimated from the correlation of the following equation 3 with respect to the average carbon number NC and the average hydrogen number NH.
TMc = α3, NC + β3, NH + γ3 ... (Equation 3)

Here, the coefficients α3, β3, and γ3 of the equation 3 are set in advance based on, for example, an experimental result or a simulation result at the time of design. Therefore, in the first embodiment, the estimation of S105 follows the equation 3 in which the preset coefficients α3, β3, and γ3 are introduced as the model data representing the cloud point TMc corresponding to the average carbon number NC and the average hydrogen number NH. It will be. Specifically, in S105, the average carbon number NC and the average hydrogen number NH calculated in S104 are introduced into the substituted equation 3 having the coefficients α3, β3, and γ3. By solving Equation 3 in which the average carbon number NC and the average hydrogen number NH are introduced in this way, the cloud point TMc corresponding to those numbers NC and NH is calculated. FIG. 4 proves that the calculated cloud point TMc can be approximately estimated with respect to the actual cloud point TMc according to the fuel components.

In the following S106 as shown in FIG. 2, the determination temperature TMj is acquired as the temperature of the fuel currently passing through the filter element 111 of the fuel filter 11 based on the detection information by the temperature sensor 15. At this time, if the temperature sensor 15 detects the fuel temperature at a location separated from the filter element 111, the determination temperature TMj is indirectly and estimatedly acquired from the temperature detected by the temperature sensor 15. On the other hand, if the temperature sensor 15 detects the fuel temperature in the vicinity of the filter element 111, the temperature detected by the temperature sensor 15 is directly acquired as the determination temperature TMj. In the first S106 that directly shifts from S105, the determination temperature TMj may be acquired based on the detection information by the temperature sensor 15 in S101.

Further, in S107, the magnitude relationship between the values TMj and TMc is determined by comparing the determination temperature TMj acquired by S106 with the cloud point TMc estimated by S105. As a result, when it is determined that the determination temperature TMj is equal to or lower than the cloud point TMc, the process proceeds to S108, while when it is determined that the determination temperature TMj exceeds the cloud point TMc, the process proceeds to S109. To do.

In S108, the filter element 111 of the fuel filter 11 is heated by controlling the heat generation of the heater 110 by adjusting the amount of energization. At this time, the heating temperature of the filter element 111 may be controlled to a variable temperature according to the difference value of the values TMj and TMc compared in S107, or may be controlled to a predetermined fixed temperature. .. On the other hand, in S109, the heating of the filter element 111 of the fuel filter 11 is stopped by stopping the heat generation of the heater 110 by cutting the amount of energization. In any of these cases S108 and S109, the process returns to S106 after the execution is completed.

As described above, in the first embodiment, the functional portion of the ECU 50 that executes S101 corresponds to the "temperature acquisition block", and the functional portion of the ECU 50 that executes S102 and S103 corresponds to the "parameter acquisition block". To do. Further, in the first embodiment, the functional portion of the ECU 50 that executes S104 corresponds to the “average calculation block”, and the functional portion of the ECU 50 that executes S105 corresponds to the “cloud point estimation block”. Further, in the first embodiment, the functional portion of the ECU 50 that executes S107 and S108 corresponds to the “heater control block”.

(Action effect)
The effects of the first embodiment described above will be described below.

In the first embodiment, the cloud point TMc of the fuel is estimated corresponding to the average number of elements of the fuel constituents calculated based on the property parameters of the fuel. According to this, since the cloud point TMc can be estimated even if the fuel components are different, the fuel filter 11 is heated under the control of the heater 110 at the determination temperature TMj below the cloud point TMc, and waxing prior to clogging. Can be deterred from. Therefore, it is possible to continuously secure the filtration efficiency of the fuel filter 11.

Moreover, according to the first embodiment, for the temperature-dependent property parameters, the correlation with the average number of elements is based on the model data expressed according to the fuel temperature, so that the average number of elements is calculated based on the property parameters. The value can be determined accurately by also based on the current temperature TMp. According to this, even if the fuel components are different, the cloud point TMc can be estimated in consideration of the temperature characteristics of the property parameters. Therefore, it is reliable to continuously secure high filtration efficiency by heating the fuel filter 11 below the cloud point TMc. It becomes possible to enhance the sex.

Here, according to the first embodiment, since the constituent components of the fuel mainly contain carbon and hydrogen, the average number of carbon elements NC and the average number of hydrogens NH are calculated to correspond to the estimated values of the cloud point TMc. By doing so, the accuracy of the estimated value can be improved. Therefore, it is possible to increase the reliability of continuously ensuring high filtration efficiency by heating the fuel filter 11 below the cloud point TMc with high estimation accuracy.

Further, according to the first embodiment, among the property parameters showing a highly sensitive correlation with the average carbon number NC and the average hydrogen number NH as the average number of elements, the current kinematic viscosity KVp and the current density DDp at the same temperature TMp Since it is based on the above, the calculated values of those values NC and NH can be accurately obtained. According to this, even if the fuel components are different, the cloud point TMc can be estimated corresponding to the accurately calculated values of the average carbon number NC and the average hydrogen number NH, so that the fuel filter 11 is heated below the cloud point TMc. This makes it possible to increase the reliability of continuous securing of high filtration efficiency.

(Second Embodiment)
The second embodiment of the present invention is a modification of the first embodiment. As shown in FIG. 5, in the heating control flow of the second embodiment, S2102 following S102, S2103 following S103, and S2104 instead of S104 are executed.

In S2102, the current kinematic viscosity KVp acquired by S102 is converted from the value at the current temperature TMp acquired by S101 to the estimated kinematic viscosity KVe which is an estimated value at the reference temperature TMb. According to the results of diligent research by the present inventor, it has been found that the amount of change in kinematic viscosity ΔKV between the current temperature TMp and the reference temperature TMb has a correlation as illustrated in FIG. 6 with respect to the current kinematic viscosity KVp. There is.

Here, for example, based on the experimental result or simulation result at the time of design, the correlation of the amount of change in kinematic viscosity ΔKV with respect to the current kinematic viscosity KVp is set in advance according to an arbitrary fuel temperature. Therefore, in the second embodiment, the conversion of S2102 follows the model data showing the correlation of the amount of change in kinematic viscosity ΔKV with respect to the current kinematic viscosity KVp according to the fuel temperature. Specifically, in S2102, among the model data corresponding to the fuel temperature of the amount of change in kinematic viscosity ΔKV with respect to the current kinematic viscosity KVp, the data corresponding to the current temperature TMp acquired by S101 is selected. Subsequently, in S2102, the amount of change in kinematic viscosity ΔKV between the current temperature TMp and the reference temperature TMb is estimated by introducing the current kinematic viscosity KVp acquired in S102 into the selected model data. Further, in S2102, the estimated kinematic viscosity change amount ΔKV is added to the current kinematic viscosity KVp acquired by S102, so that the reference temperature TMb converted from the current kinematic viscosity KVp at the current temperature TMp is used. Obtain the estimated kinematic viscosity KVe.

The reference temperature TMb is preset as a fuel temperature associated with the model data of the formulas 4 and 5 described in detail later. Further, in the model data as illustrated in FIG. 6, the plurality of dot data represent the experimental values of the amount of change in kinematic viscosity ΔKV with respect to the current kinematic viscosity KVp according to the fuel components of each region (country). Further, from the viewpoint of the storage capacity of the memory 50b and the like, when a discrete value is adopted as the fuel temperature associated with the model data in advance as illustrated in FIG. 6, the current temperature TMp between the discrete values is modeled by interpolation calculation. The data is corrected. Further, the amount of change in kinematic viscosity ΔKV is defined as a value having a positive or negative sign by subtracting the kinematic viscosity at the current temperature TMp from the kinematic viscosity at the reference temperature TMb. As a result, when the reference temperature TMb is higher than the current temperature TMp, the amount of change in kinematic viscosity ΔKV is set to the current kinematic viscosity KVp as a value having a negative sign for obtaining the estimated kinematic viscosity KVe as shown in FIG. It will be added.

As shown in FIG. 5, in S2103, the current density DDp acquired by S103 is converted from the value at the current temperature TMp acquired by S101 to the estimated density DDe which is an estimated value at the reference temperature TMb. According to the results of diligent research by the present inventor, it has been found that the estimated density DDe at the reference temperature TMb has a correlation as illustrated in FIG. 7 with respect to the current density DDp.

Here, the correlation of the estimated density DDe with respect to the current density DDp is set in advance according to an arbitrary fuel temperature, for example, based on the experimental result or the simulation result at the time of design. Therefore, in the second embodiment, the conversion of S2103 follows the model data in which the correlation of the estimated density DDe with respect to the current density DDp is expressed according to the fuel temperature. Specifically, in S2103, among the model data corresponding to the fuel temperature of the estimated density DDe with respect to the current density DDp, the data corresponding to the current temperature TMp acquired by S101 is selected. Subsequently, in S2103, by introducing the current density DDp acquired by S103 into the selected model data, the estimated density DDe at the reference temperature TMb converted from the current density DDp at the current temperature TMp is acquired.

The reference temperature TMb matches the value assumed in S2102. Further, in the model data as illustrated in FIG. 7, the plurality of dot data represent experimental values according to the fuel components of each region (country) of the estimated density DDe with respect to the current density DDp. Further, from the viewpoint of the storage capacity of the memory 50b and the like, when a discrete value is adopted as the fuel temperature associated with the model data in advance as illustrated in FIG. 7, the current temperature TMp between the discrete values is modeled by interpolation calculation. The data is corrected.

As shown in FIG. 5, in S2104, the average carbon number NC and the average hydrogen number NH based on the estimated kinematic viscosity KVe and the estimated density DDe are calculated according to the following equations 4 and 5, which are model data at the reference temperature TMb.
NC = α1, KVe + β1, NH + γ1 ... (Equation 4)
NC = α2, DDe + β2, NH + γ2 ... (Equation 5)

Here, the coefficients α1, β1, γ1 of the equation 4 and the coefficients α2, β2, γ2 of the equation 5 are set in advance in association with the reference temperature TMb by, for example, based on the experimental result or the simulation result at the time of design. Will be done. Therefore, in the second embodiment, the coefficients α1, β1, γ1 and the coefficients at the preset reference temperature TMb are used as model data showing the correlation between the estimated kinematic viscosity KVe and the estimated density DDe with respect to the average carbon number NC and the average hydrogen number NH. The calculation of S2104 follows the equations 4 and 5 in which α2, β2 and γ2 are introduced. Specifically, in S2104, the estimated kinematic viscosity KVe and the estimated density DDe acquired as the conversion values of the property parameters at the reference temperature TMb by S2102 and S2103 are obtained by the coefficients α1, β1, γ1 and the coefficients α2, β2, γ2. It is introduced into the set of the substituted equations 4 and 5. Subsequently, in S2104, the average carbon number NC and the average hydrogen number NH are calculated by solving the simultaneous equations of the set of equations 4 and 5 in which the estimated kinematic viscosity KVe and the estimated density DDe are introduced.

As described above, in the second embodiment, the functional portion of the ECU 50 that executes S2102 and S2103 corresponds to the “parameter conversion block”, and the functional portion of the ECU 50 that executes S2104 corresponds to the “average calculation block”.

According to the second embodiment described above, the temperature-dependent property parameters follow the model data at the reference temperature TMb showing the correlation with the average number of elements. Therefore, the reference temperature is obtained from the value at the current temperature TMp. The calculated value of the average number of elements based on the property parameter converted into the value in TMb can be accurately obtained. According to this, even if the fuel components are different, the cloud point TMc can be estimated in consideration of the temperature characteristics of the property parameters. Therefore, it is reliable to continuously secure high filtration efficiency by heating the fuel filter 11 below the cloud point TMc. It becomes possible to enhance the sex.

(Third Embodiment)
The third embodiment of the present invention is a modification of the first embodiment. As shown in FIG. 8, in the heating control flow of the third embodiment, S3101 following S101 and S3104 instead of S104 are executed.

In S3101, it is determined whether or not the current temperature TMp acquired by S101 matches the reference temperature TMb. At this time, the high / low judgment that the current temperature TMp matches the reference temperature TMb may be made only in a situation where the current temperature TMp matches the reference temperature TMb, or may be made in a fictitious manner in a situation where the current temperature TMp matches within a predetermined error range. Good. As a result of such S3101, if a negative determination is made due to a mismatch, the process returns to S101, while if an affirmative determination is made due to a match, the process proceeds to S102. Therefore, in S102 and S103, the current kinematic viscosity KVp and the current density DDp are acquired at substantially the same temperature as the reference temperature TMb, which is the current temperature TMp, respectively.

In S3104, the average carbon number NC and the average hydrogen number NH based on the current kinematic viscosity KVp and the current density DDp are calculated according to the following equations 6 and 7, which are model data at the reference temperature TMb.
NC = α1, KVp + β1, NH + γ1 ... (Equation 6)
NC = α2, DDp + β2, NH + γ2 ... (Equation 7)

Here, the coefficients α1, β1, γ1 of the equation 6 and the coefficients α2, β2, γ2 of the equation 7 are set in advance in association with the reference temperature TMb by, for example, based on the experimental result or the simulation result at the time of design. Will be done. Therefore, in the third embodiment, the coefficients α1, β1, γ1 and the coefficients at the preset reference temperature TMb are used as model data showing the correlation between the current kinematic viscosity KVp and the current density DDp with respect to the average carbon number NC and the average hydrogen number NH. The calculation of S3104 follows the equations 6 and 7 in which α2, β2, and γ2 are introduced. Specifically, in S3104, the current kinematic viscosity KVp and the current density DDp at the reference temperature TMb acquired as property parameters by S102 and S103 were substituted with the coefficients α1, β1, γ1 and the coefficients α2, β2, γ2. Introduce to the set of equations 6 and 7. Subsequently, in S3104, the average carbon number NC and the average hydrogen number NH are calculated by solving the simultaneous equations of the set of equations 4 and 5 in which the current kinematic viscosity KVp and the current density DDp are introduced.

In such a third embodiment, the functional portion of the ECU 50 that executes S3101, S102, and S103 corresponds to the “parameter acquisition block”, and the functional portion of the ECU 50 that executes S3104 corresponds to the “average calculation block”. ..

According to the third embodiment described above, since the temperature-dependent property parameters follow the model data at the reference temperature TMb showing the correlation with the average number of elements, the property parameters acquired at the reference temperature TMb are used. The calculated value of the average number of elements based on can be accurately obtained. According to this, even if the fuel components are different, the cloud point TMc can be estimated in consideration of the temperature characteristics of the property parameters. Therefore, it is reliable to continuously secure high filtration efficiency by heating the fuel filter 11 below the cloud point TMc. It becomes possible to enhance the sex.

(Fourth Embodiment)
The fourth embodiment of the present invention is a modification of the first embodiment. As shown in FIG. 9, in the heating control flow of the fourth embodiment, S4100 to S4104 instead of S101 to S104 are executed.

In S4100, the first current temperature TMp1 of the fuel is acquired according to the current temperature TMp of the first embodiment. In S4101, the first current kinematic viscosity KVp1 of the fuel is acquired according to the current kinematic viscosity KVp of the first embodiment at substantially the same temperature as the first current temperature TMp1 acquired by S4100.

In S4102, as the second current temperature TMp2 of the fuel, a temperature different from the first current temperature TMp1 acquired by S4100 is acquired according to the current temperature TMp of the first embodiment. In S4103, the second current kinematic viscosity KVp2 of the fuel is acquired according to the current kinematic viscosity KVp of the first embodiment at substantially the same temperature as the second current temperature TMp2 acquired by S4102.

In S4104, the average carbon number NC and the average hydrogen number NH based on the first and second current kinematic viscosities KVp1 and KVp2 are calculated by following the formula 1 described in the first embodiment as model data according to the fuel temperature. Specifically, in S4104, among the equations 1 in which the coefficients αt1, βt1, γt1 for each fuel temperature are introduced, the set of the equation 1 corresponding to the first and second current temperatures TMp1 and TMp2 acquired by S4100 and S4102 is used. ,select. Subsequently, in S4104, the first current kinematic viscosity KVp1 acquired by S4101 is introduced into the current kinematic viscosity KVp of the formula 1 selected corresponding to the first current temperature TMp1. At the same time, in S4104, the second current kinematic viscosity KVp2 acquired by S4103 is introduced into the current kinematic viscosity KVp of the formula 1 selected corresponding to the second current temperature TMp2. After this, in S4104, the average carbon number NC and the average hydrogen number NH are calculated by solving the simultaneous equations of the set of the equation 1 in which the first and second current kinematic viscosities KVp1 and KVp2 are introduced, respectively.

In such a fourth embodiment, the functional portion of the ECU 50 that executes S4100 and S4102 corresponds to the "temperature acquisition block", and the functional portion of the ECU 50 that executes S4101 and S4103 corresponds to the "parameter acquisition block". .. Further, in the third embodiment, the functional portion of the ECU 50 that executes S4104 corresponds to the “average calculation block”.

According to the fourth embodiment described above, among the property parameters showing a highly sensitive correlation with the average carbon number NC and the average hydrogen number NH as the average number of elements, the current kinematic viscosities KVp1 at a plurality of temperatures TMp1 and TMp2 By being based on KVp2, the calculated values of those values NC and NH can be accurately obtained. According to this, even if the fuel components are different, the cloud point TMc can be estimated corresponding to the accurately calculated values of the average carbon number NC and the average hydrogen number NH, so that the fuel filter 11 is heated below the cloud point TMc. This makes it possible to increase the reliability of continuous securing of high filtration efficiency. In the fourth embodiment, the detection information of the density sensor 17 or the sensor 17 itself is not required in order to exert the effect.

(Fifth Embodiment)
The fifth embodiment of the present invention is a modification of the fourth embodiment. As shown in FIG. 10, in the heating control flow of the fifth embodiment, S5101, S5103, and S5104 are executed instead of S4101, S4103, and S4104, respectively.

In S5101, the first current density DDp1 of the fuel is acquired according to the current density DDp of the first embodiment at substantially the same temperature as the first current temperature TMp1 acquired by S4100. In S5103, the second current density DDp2 of the fuel is acquired according to the current density DDp of the first embodiment at substantially the same temperature as the second current temperature TMp2 acquired by S4101.

In S5104, the average carbon number NC and the average hydrogen number NH based on the first and second current densities DDp1 and DDp2 are calculated by following the formula 2 described in the first embodiment as model data according to the fuel temperature. Specifically, in S5104, among Equation 2 in which the coefficients αt2, βt2, and γt2 for each fuel temperature are introduced, the set of Equation 2 corresponding to the first and second current temperatures TMp1 and TMp2 acquired by S4100 and S4102 is used. ,select. Subsequently, in S5104, the first current density DDp1 acquired by S5101 is introduced into the current density DDp of the formula 2 selected corresponding to the first current temperature TMp1. At the same time, in S5104, the second current density DDp2 acquired by S5103 is introduced into the current density DDp of the formula 2 selected corresponding to the second current temperature TMp2. After this, in S5104, the average carbon number NC and the average hydrogen number NH are calculated by solving the simultaneous equations of the set of the equations 2 in which the first and second current densities DDp1 and DDp2 are introduced, respectively.

In such a fifth embodiment, the functional portion of the ECU 50 that executes S5101 and S5103 corresponds to the "parameter acquisition block", and the functional portion of the ECU 50 that executes S5104 corresponds to the "average calculation block".

According to the fifth embodiment described above, among the property parameters showing a highly sensitive correlation with the average carbon number NC and the average hydrogen number NH as the average number of elements, the current densities DDp1 and DDp2 at a plurality of temperatures TMp1 and TMp2. Based on the above, the calculated values of these values NC and NH can be accurately obtained. According to this, even if the fuel components are different, the cloud point TMc can be estimated corresponding to the accurately calculated values of the average carbon number NC and the average hydrogen number NH, so that the fuel filter 11 is heated below the cloud point TMc. This makes it possible to increase the reliability of continuous securing of high filtration efficiency. In the fifth embodiment, the detection information of the kinematic viscosity sensor 16 or the sensor 16 itself is unnecessary in order to exert the effect.

(Other embodiments)
Although a plurality of embodiments of the present invention have been described above, the present invention is not construed as being limited to those embodiments, and may be applied to various embodiments and combinations without departing from the gist of the present invention. Can be applied.

Specifically, in the first modification of the first to fifth embodiments, the current temperatures TMp, TMp1, TMp2 and the determination temperature TMj may be acquired by estimation based on the operating conditions of the internal combustion engine 1. In this modification 1, the detection information of the temperature sensor 15 or the sensor 15 itself is not required in order to exert the effect. Further, in the modification 1, as the operating conditions used for estimating the current temperatures TMp, TMp1, TMp2 and the determination temperature TMj, for example, the frequency of use such as the low pressure condition and the medium pressure condition of the fuel after the internal combustion engine 1 is completely warmed up. The large condition of is adopted.

In the second modification relating to the fourth embodiment, another kinematic viscosity sensor of substantially the same type is installed at a position different from the kinematic viscosity sensor 16 in the fuel path of the fuel system 10, so that the second current kinematic viscosity KVp2 is different. It may be acquired based on the detection information of the kinematic viscosity sensor of. In this modification 2, the second current temperature TMp2 at the installation location of another kinematic viscosity sensor is acquired according to the current temperature TMp of the first embodiment.

In the third modification relating to the fourth embodiment, the first and second reference temperatures converted from the first and current kinematic viscosities KVp1 and KVp2 at the first and second current temperatures TMp1 and TMp2 according to the second embodiment, respectively. The average carbon number NC and the average hydrogen number NH may be calculated by individually introducing the values of the above into the set of the formula 1 corresponding to each of the reference temperatures. In the modified example 4 relating to the fourth embodiment, the first and current kinematic viscosities KVp1, KVp2 at the first and second current temperatures TMp1 and TMp2, which match the first and second reference temperatures, respectively, according to the third embodiment. However, the average carbon number NC and the average hydrogen number NH may be calculated by individually introducing them into the set of the formula 1 corresponding to each of the reference temperatures.

In the fifth modification of the fifth embodiment, the density sensor of substantially the same type is separately installed at a position different from the density sensor 17 in the fuel path of the fuel system 10, so that the second current density DDp2 is the other density sensor. It may be acquired based on the detection information. In this modification 5, the second current temperature TMp2 at the installation location of another density sensor is acquired according to the current temperature TMp of the first embodiment.

In the sixth modification regarding the fifth embodiment, the first and second current densities DDp1 and DDp2 converted from the first and second current temperatures TMp1 and TMp2 according to the second embodiment are used at the first and second reference temperatures, respectively. The average carbon number NC and the average hydrogen number NH may be calculated by individually introducing the values into the set of the formula 2 corresponding to each of the reference temperatures. In the modified example 7 relating to the fifth embodiment, the first and second current densities DDp1 and DDp2 at the first and second current temperatures TMp1 and TMp2, which match the first and second reference temperatures, respectively, according to the third embodiment. The average number of carbon atoms NC and the average number of hydrogens NH may be calculated by individually introducing them into the set of the formula 2 corresponding to each of the reference temperatures.

In the modified example 8 relating to the first to fifth embodiments, at least a part of the steps of the heating control flow is realized by hardware by one or more ICs instead of being functionally realized by the ECU 50. May be good.

1 Internal combustion engine, 1a combustion chamber, 10 fuel system, 11 fuel filter, 15 temperature sensor, 16 kinematic viscosity sensor, 17 density sensor, 50 ECU, 50a processor, 50b memory, 110 heater, 111 filter element, DDp current density, DDp1 1st current density, DDp2 2nd current density, DDe estimated density, KVp current kinematic viscosity, KVp1 1st current kinematic viscosity, KVp2 2nd current kinematic viscosity, KV estimated kinematic viscosity, ΔKV kinematic viscosity change, NC average carbon number NH average hydrogen number, TMc cloud point, TMj judgment temperature, TMp current temperature, TMp1 first current temperature, TMp2 second current temperature, TMb reference temperature,

Claims (8)

A fuel system control device (50) that controls heating by a heater (110) of a fuel filter (11) that filters fuel supplied to a combustion chamber (1a) in the fuel system (10) of an internal combustion engine (1). ,
Parameter acquisition blocks (S102, S103, S3101, S4101, S4103, S5101, S5103) for acquiring property parameters (KVp, DDp, KVp1, KVp2, DDp1, DDp2) representing the properties of the fuel, and
An average calculation block (S104, S2104, S3104, S4104, S5104) for calculating the average number of elements (NC, NH) of the components constituting the fuel based on the property parameter acquired by the parameter acquisition block.
A cloud point estimation block (S105) that estimates the cloud point (TMc) of the fuel corresponding to the average number of elements calculated by the average calculation block, and a cloud point estimation block (S105).
A fuel including heater control blocks (S107, S108) that heat the fuel filter by controlling the heater at the temperature (TMj) of the fuel that is equal to or lower than the cloud point estimated by the cloud point estimation block. System control device. A temperature acquisition block (S101, S4100, S4102) for acquiring the current temperature (TMp, TMp1, TMp2) of the fuel is further provided.
The parameter acquisition block (S102, S103, S4101, S4103, S5101, S5103) acquires the property parameters (KVp, DDp, KVp1, KVp2, DDp1, DDp2) at the current temperature acquired by the temperature acquisition block. And
The average calculation block (S104, S4104, S5104) is the data acquired by the parameter acquisition block according to model data set according to the temperature of the fuel as data representing the correlation of the property parameters with the average number of elements. The fuel system control device according to claim 1, wherein the average number of elements is calculated based on the property parameters and the current temperature acquired by the temperature acquisition block. A temperature acquisition block (S101) for acquiring the current temperature (TMp) of the fuel, and
The property parameters (KVp, DDp) acquired by the parameter acquisition block (S102, S103) are changed from the value at the current temperature acquired by the temperature acquisition block to the value (KVe,) at the reference temperature (TMb). A parameter conversion block (S2102, S2103) for converting to DDe) is further provided.
The average calculation block (S2104) is converted from the value acquired by the temperature acquisition block by the parameter conversion block according to the model data at the reference temperature set as data representing the correlation of the property parameters with respect to the average number of elements. The fuel system control device according to claim 1, wherein the average number of elements is calculated based on the property parameters. The parameter acquisition block (S102, S103, S3101) acquires the property parameters (KVp, DDp) at the reference temperature (TMb), and obtains the property parameters (KVp, DDp).
The average calculation block (S3104) is based on the property parameters acquired by the parameter acquisition block according to the model data at the reference temperature set as data representing the correlation of the property parameters with respect to the average number of elements. The fuel system control device according to claim 1, wherein the average number of elements is calculated. The average calculation block (S104, S2104, S3104, S4104, S5104) is composed of the average number of carbon elements (NC), which is the average number of carbon elements constituting the fuel, and the average number of elements of hydrogen constituting the fuel. Calculate a certain average hydrogen number (NH),
The fuel according to any one of claims 1 to 4, wherein the cloud point estimation block (S105) calculates the cloud point based on the average carbon number and the average hydrogen number calculated by the average calculation block. System control device. The parameter acquisition block (S102, S103, S3101) is any one of claims 1 to 5 for acquiring the kinematic viscosity (KVp) and density (DDp) of the fuel at the same temperature (TMp) as the property parameters. The fuel system control device described in the section. The parameter acquisition block (S4101, S4103) is described in any one of claims 1 to 5 for acquiring the kinematic viscosities (KVp1, KVp2) of the fuel at a plurality of temperatures (TMp1, TMp2) as the property parameters. Fuel system controller. The parameter acquisition block (S5101, S5103) according to any one of claims 1 to 5, wherein the density (DDp1, DDp2) of the fuel at a plurality of temperatures (TMp1, TMp2) is acquired as the property parameter. Fuel system controller.

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